#include <stdio.h>
int My_strlen(char* string){
	int ans = 0;
	while(*string){
		ans++;
		string++;
	}
	return ans;
}
int reverse_string(char * string){
	char ch = '\0';
	ch = string[0];
	int num = 0;
	num = My_strlen(string);
	if(num <= 1)
		return 0;
	string[0] = string[num - 1];
	string[num - 1] = '\0';
	reverse_string(string+1);
	string[num - 1] = ch;
}
int main(){
	char str[] = "abcdef";
	reverse_string(str);
	printf("%s",str);
	return 0; 
}

